bytev-charts-beta/lib/plugin/three.js/examples/js/exporters/OBJExporter.js

基于echarts和JavaScript及ES6封装的一个可以直接调用的图表组件库，内置主题设计，简单快捷，且支持用户自定义配置； npm 安装方式: npm install bytev-charts 若启动提示还需额外install插件,则运行 npm install @babel/runtime-corejs2 即可;

import "core-js/modules/es.function.name.js";
import "core-js/modules/es.array.join.js";
console.warn("THREE.OBJExporter: As part of the transition to ES6 Modules, the files in 'examples/js' were deprecated in May 2020 (r117) and will be deleted in December 2020 (r124). You can find more information about developing using ES6 Modules in https://threejs.org/docs/#manual/en/introduction/Installation.");

THREE.OBJExporter = function () {};

THREE.OBJExporter.prototype = {
  constructor: THREE.OBJExporter,
  parse: function parse(object) {
    var output = '';
    var indexVertex = 0;
    var indexVertexUvs = 0;
    var indexNormals = 0;
    var vertex = new THREE.Vector3();
    var normal = new THREE.Vector3();
    var uv = new THREE.Vector2();
    var i,
        j,
        k,
        l,
        m,
        face = [];

    var parseMesh = function parseMesh(mesh) {
      var nbVertex = 0;
      var nbNormals = 0;
      var nbVertexUvs = 0;
      var geometry = mesh.geometry;
      var normalMatrixWorld = new THREE.Matrix3();

      if (geometry instanceof THREE.Geometry) {
        geometry = new THREE.BufferGeometry().setFromObject(mesh);
      }

      if (geometry instanceof THREE.BufferGeometry) {
        // shortcuts
        var vertices = geometry.getAttribute('position');
        var normals = geometry.getAttribute('normal');
        var uvs = geometry.getAttribute('uv');
        var indices = geometry.getIndex(); // name of the mesh object

        output += 'o ' + mesh.name + '\n'; // name of the mesh material

        if (mesh.material && mesh.material.name) {
          output += 'usemtl ' + mesh.material.name + '\n';
        } // vertices


        if (vertices !== undefined) {
          for (i = 0, l = vertices.count; i < l; i++, nbVertex++) {
            vertex.x = vertices.getX(i);
            vertex.y = vertices.getY(i);
            vertex.z = vertices.getZ(i); // transform the vertex to world space

            vertex.applyMatrix4(mesh.matrixWorld); // transform the vertex to export format

            output += 'v ' + vertex.x + ' ' + vertex.y + ' ' + vertex.z + '\n';
          }
        } // uvs


        if (uvs !== undefined) {
          for (i = 0, l = uvs.count; i < l; i++, nbVertexUvs++) {
            uv.x = uvs.getX(i);
            uv.y = uvs.getY(i); // transform the uv to export format

            output += 'vt ' + uv.x + ' ' + uv.y + '\n';
          }
        } // normals


        if (normals !== undefined) {
          normalMatrixWorld.getNormalMatrix(mesh.matrixWorld);

          for (i = 0, l = normals.count; i < l; i++, nbNormals++) {
            normal.x = normals.getX(i);
            normal.y = normals.getY(i);
            normal.z = normals.getZ(i); // transform the normal to world space

            normal.applyMatrix3(normalMatrixWorld).normalize(); // transform the normal to export format

            output += 'vn ' + normal.x + ' ' + normal.y + ' ' + normal.z + '\n';
          }
        } // faces


        if (indices !== null) {
          for (i = 0, l = indices.count; i < l; i += 3) {
            for (m = 0; m < 3; m++) {
              j = indices.getX(i + m) + 1;
              face[m] = indexVertex + j + (normals || uvs ? '/' + (uvs ? indexVertexUvs + j : '') + (normals ? '/' + (indexNormals + j) : '') : '');
            } // transform the face to export format


            output += 'f ' + face.join(' ') + "\n";
          }
        } else {
          for (i = 0, l = vertices.count; i < l; i += 3) {
            for (m = 0; m < 3; m++) {
              j = i + m + 1;
              face[m] = indexVertex + j + (normals || uvs ? '/' + (uvs ? indexVertexUvs + j : '') + (normals ? '/' + (indexNormals + j) : '') : '');
            } // transform the face to export format


            output += 'f ' + face.join(' ') + "\n";
          }
        }
      } else {
        console.warn('THREE.OBJExporter.parseMesh(): geometry type unsupported', geometry);
      } // update index


      indexVertex += nbVertex;
      indexVertexUvs += nbVertexUvs;
      indexNormals += nbNormals;
    };

    var parseLine = function parseLine(line) {
      var nbVertex = 0;
      var geometry = line.geometry;
      var type = line.type;

      if (geometry instanceof THREE.Geometry) {
        geometry = new THREE.BufferGeometry().setFromObject(line);
      }

      if (geometry instanceof THREE.BufferGeometry) {
        // shortcuts
        var vertices = geometry.getAttribute('position'); // name of the line object

        output += 'o ' + line.name + '\n';

        if (vertices !== undefined) {
          for (i = 0, l = vertices.count; i < l; i++, nbVertex++) {
            vertex.x = vertices.getX(i);
            vertex.y = vertices.getY(i);
            vertex.z = vertices.getZ(i); // transform the vertex to world space

            vertex.applyMatrix4(line.matrixWorld); // transform the vertex to export format

            output += 'v ' + vertex.x + ' ' + vertex.y + ' ' + vertex.z + '\n';
          }
        }

        if (type === 'Line') {
          output += 'l ';

          for (j = 1, l = vertices.count; j <= l; j++) {
            output += indexVertex + j + ' ';
          }

          output += '\n';
        }

        if (type === 'LineSegments') {
          for (j = 1, k = j + 1, l = vertices.count; j < l; j += 2, k = j + 1) {
            output += 'l ' + (indexVertex + j) + ' ' + (indexVertex + k) + '\n';
          }
        }
      } else {
        console.warn('THREE.OBJExporter.parseLine(): geometry type unsupported', geometry);
      } // update index


      indexVertex += nbVertex;
    };

    object.traverse(function (child) {
      if (child instanceof THREE.Mesh) {
        parseMesh(child);
      }

      if (child instanceof THREE.Line) {
        parseLine(child);
      }
    });
    return output;
  }
};